The intention of this was to create a safe space for us both where we can turn down the intensity of the drama while we get clear.
I understand what you are going for with the idea. But in practice, it makes zero sense. The timing is so arbitrary and the atmosphere isnt going to be any "safer". The only way to turn down the intensity is to turn down the intensity. It has nothing to do with this 3-4 week "grace period".

Anyhow, I spoke too soon. When my W got up, she came to me and said that she is back to being certain that she wants to consider this a trial separation.
Oh? How did that 3-4 weeks turn out?

Later today, we ran into a conflict with regard to her OCD again. My need to GAL and my increased need for support from my friends and family means that I really want to have friends over. I am trying to organize a gathering on New Year's Eve tomorrow for my parents and invite some of my other friends, but my W is putting roadblocks at every turn. She doesn't want certain friends to come who she doesn't like even though they are very dear to me. She doesn't want people to invite their kids along because kids are particularly "dirty".
From what you describe, I assume that this isnt the first time youve tried to do something like this. How are you trying to arrange.handle this differently than before? If you know it hasnt worked before, why would this time be any different? Instead of thinking of your W as putting up roadblocks, how can you compromise?

For reference, here here is a post from one month ago where I went into detail on my W's OCD. This problem long pre-dates her waywardness and has always been a serious issue for me, along with her avoidance behavior and complete disinterest in ever working through a single conflict collaboratively.
I think that we have discussed some of that before. She doesnt want to approach problems in the same way as you, so she is wrong in your eyes.

Our counselor agrees that my W does have a serious OCD problem. She and other friends have advised me that I really should stop being a doormat and tolerating this by being compliant with it and minimizing my needs as an equal member of our household. I have suppressed my anger about this for long enough and now that I'm even more in need of connecting with other friends than ever, I just can't put up with this anymore.

I know that many people here are entirely against divorce, no matter what. I am not... and I am feeling more certain than ever that this is what I want now, for multiple reasons:
Nobody here is in favor of maintaining every single marriage 100% of the time. But, the reasons for divorcing should be incredibly convincing. Have you read DR? The first chapter that goes through all kinds of statistics and impacts of divorce is incredibly harrowing. I dont think I would get divorced based on a feeling or two...

1. I simply cannot live with a woman who has an OCD problem like this and won't even admit that it is a problem, and is completely selfish about it to the extent of causing extreme resentment in me.
So, it's been 10 years together, and NOW, all of a sudden, you CANNOT live like this? Seems convenient.

I understand how resentment can build after years of unmet needs. Ill ask again about if you have read DR? Basically, the point is that people can change. What can YOU do to instill a POSITIVE change in your W's behaviors?

2. I have tried throughout our entire R to respectfully discuss things when I recognize a conflict or problem that poses a threat to the M. This includes confronting my W many, many times as long as 4 years ago about her obvious fading attraction to me. She always avoided it and wouldn't even talk about it. I need a partner who is actually willing to talk through problems with me and grow together in the M.
What you said doesnt sound terribly respectful. Again, doing the same thing over and over again and expecting different results is madness. What have you done differently?

3. She has cheated on me, was dishonest and hid it for 2 years. This caused extreme damage to my trust as well as to the way that I see her as a person. I really don't know if I can put this behind me, even if she was to become interested in trying to earn back my trust.
Fair. But are you ready to push divorce forward without KNOWING for sure?

4. She hid doubts about getting married from the very beginning. She never disclosed the fact that she really didn't want to have a child, and went ahead and had our son anyways because she was too scared to confront me about it. She hid this for 8 years!
I wouldnt believe anything she said while she was/is wayward. Its very easy to rewrite history. My XW told me she was unhappy for many years before we separated. Even though we had a second child during that time. Do you really think a person could be unhappy for, say, 5 years, and have her spouse really not know?

5. She does not want a 2nd child, and I really do.
Again, youre listening to things she is saying NOW. Do you really want a second child. with her. right now. ?

6. She is very different from me and we have few interests in common. We have completely different friends and different lives. When I try to do things together, she has always resisted, even long before she became wayward.
And how did you approach this? Proposing things you want to do? Asking her what she wants to do? Picking something to do you think she would like?

7. I have been feeling very good since yesterday about the idea of splitting.
How do you feel after you eat a delicious meal? How do you feel three days later? Is it the same?

8. My parents divorced when I was 12, and it wasn't nearly as damaging as many divorces that I hear about. Both my sister and I were glad that they did. Both of my parents ended up in much happier 2nd marriages which have lasted and are still going. So I have a good model for how to divorce in a way that is least damaging.
Sure. And here you are, right? So what kind of example are you setting for your child? Be aware that having good second marriages is RARE. The divorce rate is high. The divorce rate for second marriages is HIGHER.

9. My W and I are mutually aligned on this now. We both want a clean divorce and we want to stay friends and put our son first. No lawyers, just a mediator. I'm confident that we can do it in a way that isn't messy and minimizes damage to our son.
Easy to say. Next to impossible to do. Heard that from my XW as well. Not at all how it went down.